The D4R Pro to replace the D4 dovetail jig

Lies, and more lies

I lied recently; and I also lied some time ago.

I lied some time ago, when I said I would not get rid of my D4 dovetail jig. Then Megan suggested I ditch the old dovetail jig, as I can now competently hand-cut through dovetails, and half-blind dovetails; I lied, because the D4 has been a workhorse in my shop for many years – I did not intend to ditch it, replace it. It works hard when I make multiple drawers, boxes, cases, etc.

I lied, because now I can ditch the D4 jig <sigh…> But I am a happy! Honest – I am very, very happy! Because…

I now have the D4R Pro jig

It all changed Friday (this past Friday). Sandy called me while I was in the shop, to let me know she had something I did not have (neener, neener…). What the… Hmmm – what was going on? She finally broke the news (she was pulling my leg). Two packages from Leigh Industries were delivered just minutes before: a brand-new D4R Pro dovetail jig, and a new VRS (Vacuum and Router Support).

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3/8-inch finger joints made on the D4R Pro.

I spent part of Saturday finishing the installation of the jig. And on Sunday I tweaked the installation, and spent time getting to know the ins and outs of making small (3/8-inch) finger joints. I documented my work in a 5-minute video (see below), to show how easy it is to make the finger joints with the jig.

Impressions:

Fit and finish.Classic Leigh product – nice, tight fit of all parts that must be assembled to the main body of the jig. My only difficulty was with the threads one of the bolts that hold the clamps to the body – and this was minor, as the nut mounted properly, without damage to its threads (simple debris, from cutting the threads). The finger assembly was almost perfect; all guide fingers were attached to the bars nicely – and all but one of the machine screws holding the fingers in place popped nicely when loosened, just as they are supposed to pop to allow movement of each finger. I must check more closely to determine what might be going on with the one finger, as it remains relatively tight, and is harder to move than others.

Finger joints. A little while ago I wrote about having to make a lot of boxes. I started making a bunch of little boxes on the old, trusty D4 jig equipped with the F3 finger joint template. The old D4 made 1/4-inch finger joints, but it required precise machining of spacers, which had to be taped to the body of the jig. And if the tape slipped even a little bit, all the fun would go to waste. That was the main reason I was ecstatic when I received the F3 template (it makes it possible to make a whopping 11 different sizes of square finger joints, plus 3 sizes of half-blind finger joints!)

Making finger joints. On Saturday I learned the adjustments to the D4R Pro to make finger joints. And on Sunday I made some 3/8-inch finger joints, and documented the process in the video below. The steps are easy; if I can do this, anyone can do it. It is dead simple; the steps are as follows:

Adjust finger assembly for finger joints, and lower the assembly onto the support board.

Insert and clamp the first board. For very thin boards this can be a bit tricky on the older D4, as you must ensure the edges are square to the sides top, and flush to the bottom of the finger assembly. With the D4R Pro this is much easier, as the integral side stops are always perfectly square to the jig body, and to the finger assembly.

Mark and adjust the depth of cut to the mating boards.

Raise the finger assembly, and adjust the guide fingers using the spacer with the straight edges, not the one with the dovetail shape on one edge. In the video I illustrate how to first set the horizontal spacing between adjacent finger pairs, and then use the spacer aligned vertically to adjust the spacing between the fingers in each pair.

I confirmed correct spacing adjustments using calipers. I do this, especially when getting familiar with new equipment, to confirm I am doing things correctly. Three different times I set the larger spacing incorrectly; I simply redid the finger setup, avoiding sloppy configuration.

When finished making all the guide finger adjustments, lower the finger assembly onto the support board.

Use two scrap boards to make a test joint:

Route one end of the scrap board, making the cuts between all openings. Run the router along the sides of both fingers.

insert the spacer in the jig body, insert the second scrap board into the jig and push against the spacer. Route this board.

Remove the second board, and test with the first board for joint fit. If too loose or too tight, the e7 guide bush mounted to the router base allows adjusting the fit in 0.001″ increments (that is one-thousand of an inch!).

Once the proper fit is achieved, it is time to make a box. Simply route opposite sides of the box first; then insert the spacer and route the second set of boards.

The entire process is easy. And no special template is required to make two sizes of box joints. This is a very nice improvement in the D4R Pro over the much older D4 jig!

What about the F3 template?

This is good news, as the F3 fits the D4R Pro perfectly. I will keep the F3. But I will need it only when I make finger joints different from 3/8″ or ¾”!

Summary

I was able to set up the D4R Pro in just a couple of hours. It helped that I was familiar with the D4 – take it step-by-step, with assembly instructions well documented in the User Guide; it may take YOU 2 hours and 1 minute, or only one hour. In the video I used maple to make the test joint. I also made test joints using sycamore, and quarter-sawn white oak, using thin and thick boards. I believe that using thicker boardsmakes it more demanding to get a perfect joint fit, as the wood cannot be compressed readily. In all cases, the fit was excellent. I can now (maybe) ditch the D4!

The bottom line: Leigh has pulled quite a feat modifying the D4R to make finger joints. At the same time they improved the jig by making it possible to make half-blind dovetail joints in one pass. I will cover this feature in a future article.

I would like to hear from you:

Do you make boxes (large or small) with finger joints?

If you do, are you already using a special jig or template?

Regardless the system you currently use to make finger joints, are you happy with the joint fit you get?

Or are you so frustrated that you are ready to renounce making finger joints…period?

Do you believe this may mean you are ready for the D4R, and eventually the F3 for the D4R. Ready – get set – GO!

About Al Navas

I love working with wood, and sharing here on the blog. I also love designing items that my clients will love having in their homes and offices. Please let me know if you need a special piece to share with your loved ones. Freelance, Legal, and Community Interpreter. Love photography.

I found the box joint procedure in the Super Jig User Guide. It starts on Page 55, Chapter 14. The procedure looks quite similar to what I used for the D4R Pro!

The major difference is that the Super Jigs make 5/16″ and 5/8″ finger joints, while the D4R Pro makes 3/8″ and 3/4″ finger joints – *just* a bit smaller on the Super Jigs. You will love making these on your Super Jig!